In the aforesaid co-pending application is disclosed a top assembly for an open mouth coffee pot having flow passage means extending therethrough and wherein the flow passage means includes a liquid trap. The purpose of the liquid trap is to retain a volume of coffee therein to act as a liquid seal in preventing atmospheric contact with the pot contained coffee; all as more specifically disclosed in the aforesaid copending application. One of the simpler forms the liquid trap may assume is a hook-shaped, or "J" shaped, tube as illustrated in FIGS. 3 and 5 of the aforesaid copending application. The top assemblies shown in the aforesaid FIGS. 3 and 5 may be made by joining a bent tube with the remainder of the top assembly as by sonic welding, adhesives or the like.
The problem arises in connection with mass production requirements. The entire top assembly cannot be injection molded as a single part because of the required J bend to form the liquid trap. Consequently, the J-shaped tube must be formed separately and subsequently joined to the remainder of the top assembly. The J-shaped tube, too, cannot be molded as a single piece because the required radius of curvature, to retain the liquid seal, is such that cooperating tool parts cannot make the necessary convergence. Thus, the J bend would have to be formed in two halves and then joined to form the J tube. Similarly, it would be possible to bend drawn tubing into a J shape while it is still hot, but it is still required that the J tube be joined to the remainder of the top assembly.
In any of the above events, a joining step is required. Because of the environment in which the top assembly is used, the plastics that may be employed are limited to those which will meet FDA requirements for hot food contact. Among the available choices only polypropylene offers a significant cost advantage since it is about one-third the price of the next most inexpensive plastic that may be used, such as polycarbonate, for example. Unlike most other plastics, polypropylene cannot be joined by welding, glueing or any other known manner of joining most plastics.
It is, therefore, the purpose of the invention to produce a top assembly having a J-shaped liquid trap from two injection molded parts that need be only mechanically interfitted as opposed to a permanent joining.